Custom modeline on X.Org

For running X

xrandr --newmode uw 295.08  2560 2744 3024 3488  1080 1081 1084 1128 -HSync +Vsync
xrandr --addmode DP2 uw
xrandr --output DP2 --mode uw

Generating modeline

Generalized Timing Formula

Wikipedia

$ gtf

usage: gtf x y refresh [-v|--verbose] [-f|--fbmode] [-x|--xorgmode]

            x : the desired horizontal resolution (required)
            y : the desired vertical resolution (required)
      refresh : the desired refresh rate (required)
 -v|--verbose : enable verbose printouts (traces each step of the computation)
  -f|--fbmode : output an fbset(8)-style mode description
 -x|--xorgmode : output an Xorg-style mode description (this is the default
                if no mode description is requested)

VESA Coordinated Video Timings

Wikipedia

The standard was adopted in 2002 and superseded the Generalized Timing Formula.

$ cvt

usage: cvt [-v|--verbose] [-r|--reduced] X Y [refresh]

 -v|--verbose : Warn about CVT standard adherence.
 -r|--reduced : Create a mode with reduced blanking (default: normal blanking).
            X : Desired horizontal resolution (multiple of 8, required).
            Y : Desired vertical resolution (required).
      refresh : Desired refresh rate (default: 60.0Hz).

Calculates VESA CVT (Coordinated Video Timing) modelines for use with X.